1. Field of the Invention
This invention relates to a video signal processing device, and more particularly to an improvement of a video printer for printing out desired picture data stored in a memory, for example.
2. Description of the Prior Art
In a commonly termed video printer, a video signal VI output from a video tape recorder or the like is converted into digital data, which is stored in a frame memory, the stored picture data being read out for printing on printing paper.
The picture data is stored in the memory either in a frame memory mode or in a field memory mode, these modes being for free selection by the user depending on the subject picture data to be printed.
In the frame memory mode, two fields of picture data are stored as one frame in a storage area of a memory. In the field memory mode, the individual fields of picture data are stored in separate fields of the storage region of the memory.
Picture data stored in the memory is printed on printing paper either in a frame printing mode or in a field printing mode, and these modes are selected discretionally by the user.
In the frame printing mode, the two fields of picture data stored in the memory are directly printed. In the field printing mode, the picture data stored in the memory is divided into two fields, and only one thereof is printed.
Usually, for obtaining a high definition and high quality print of video data, still picture data, picture data stored in the frame memory mode may be printed in the frame printing mode. On the contrary, when motion picture, the field memory mode may be selected on storing picture data, or the field printing mode may be selected on printing picture data.
This is no reason that if motion picture data is written in the frame memory mode (as shown in FIG. 1A), a blur is produced due to the time difference between individual fields A and B of the picture. If the field memory mode is selected for writing data (as shown in FIG. 1B), only field A of the picture (i.e., picture data A1, A2, . . . , An) are stored, and thus there is no blur, thus permitting high picture quality to be obtained.
Since the above modes are for free selection by the user, in a division storage mode, in which a plurality of frames are stored in a divided fashion in a memory, a selection like that in case of a full size mode, in which one frame of picture data is stored in the memory, is done, and therefore the picture quality is rather deteriorated.
For example, when motion picture data is stored in a one-fourth division storage mode in the memory, like the case of the full size mode, there is a case of selecting the field memory mode to prevent blurring of the motion picture.
However, in the one-fourth division mode, one field of picture data is contracted and stored in four storage region divisions, that is, a field A obtained by thinning out the scanning lines into one-half in the vertical direction is stored.
If the field memory mode is selected at this time, coarser picture data (A1, A3, . . . , Am, m=n-1) of the field A is stored, as shown in FIG. 2B. Since the frame is contracted, the print of picture data is liable to be considerably deteriorated.
Likewise, if the field printing mode is selected by the user on printing, only a single field is printed in the one-fourth division storage region, and therefore the obtainable print of picture data inevitably has deteriorated picture quality.